Surface stabilized ferroelectric liquid crystal devices

Abstract

A liquid crystal device including a ferroelectric liquid crystal disposed between plates treated to enforce a particular ferroelectric molecular orientation to the plates. The devices employ alone or in combination non-planar boundary conditions, polar boundary conditions, boundaries with multiple physical states, intrinsic spontaneous splay distortion of the polarization orientation field, combined ferroelectric and dielectric torques, layers tilted with respect to the plates. The plates are spaced by a distance sufficiently small to ensure unwinding of the helix typical in a bulk of the material to form either monostable, bistable or multistable states which exhibit novel electro-optic properties. The liquid crystal is responsive to an externally applied electric field, temperature or the like to make a light valve or other electro-optical device.

What is claimed is: 
     
       1. An electro-optical device comprising: a pair of substrates;   a ferroelectric liquid crystal having a plurality of layers each comprised of a plurality of molecules, each molecule having a long axis, the long axes of said molecules in a bulk forming helices, said ferroelectric liquid crystal being disposed between said pair of substrates which are spaced by a distance sufficiently small to suppress the formation of said helices, said plurality of layers being aligned parallel to each other, and said substrates and said ferroelectric liquid crystal defining a plurality of stable orientation states of said molecular long axes; and   means for causing light passing through said liquid crystal in one of said plurality of orientation states to be one color and light passing through said liquid crystal in another of said plurality of stable states to be different color.   
     
     
       2. A liquid crystal device comprising: a pair of substrates;   a ferroelectric liquid crystal having a plurality of layers each comprised of a plurality of molecules, each molecule having a long axis, the long axes of said molecules in a bulk forming helices, said ferroelectric liquid crystal being disposed between said pair of substrates which are spaced by a distance sufficiently small to suppress the formation of said helices, said plurality of layers being aligned parallel to each other, and said substrates and said ferroelectric liquid crystal causing at least two orientation states of said molecular long axes which correspond to at least two of a plurality of different stable states, said at least two orientation states being separated by domain walls.   
     
     
       3. A liquid crystal display according to claim 2 further comprising means for applying an electric field intersecting the normal of said layers.